1. Field of the Invention
The present invention relates to an armature of a moving coil type linear motor and a method for assembling the same.
2. Description of the Conventional Art
FIG. 1 shows a perspective view of a moving coil type linear motor consisting of a movable element 20 and a stator element 10. The stator element 10 includes a U-shaped armature frame 11 and permanent magnets 12 arranged on inner surfaces of the armature frame 11. The movable element 20 disposed in the U-shaped armature frame 11 consists of a frame 21 and a coil block 22. When the coil block 22, formed by molded coils (not shown), is supplied with electric current, a thrust is generated between the coil block and the permanent magnets 12, causing the movable element 20 to be linearly moved.
In order to couple the coil block 22 into the armature frame 21 as shown in FIG. 2a, there are formed a groove 21a in a central region of the armature frame 21, and spacers 21b located at a constant interval in the groove 21a. The coil block is formed as follows: the coils 22a are first placed between the spacers 21b; and the electrical wiring between the coils 22a and then the molding for forming the coil block 22 are sequentially conducted. The groove 21a and the spacers 21b are needed to regulate the pitch between the coils 22a and the height thereof in assembling the coils.
In the prior art described above, when the coreless coils 22a are assembled, the coil sizes are utilized to maintain the constant height of the coils, and therefore the precise assembling becomes required. Further, to maintain a constant pitch between the coils 22a, the machined spacers 21b are also needed.
The movable element 20 is assembled in such a manner that a linear movement of the movable element 20 along the axial direction of the stator element 10 becomes made possible. For this, it is required to wire and assemble the coils 22a at a constant interval, which will be described below with reference to FIG. 2b. 
As shown in FIG. 2b, the armature, i.e., movable element 20, includes the armature frame 21 and the armature coils 22a forming the coil block 22, wherein the armature frame 21 is formed with the groove 21a in a central portion thereof and has one side thereof formed with a hole 21c through which lead lines 21d are placed for external connection.
The armature coils 22a to be assembled into the groove 21a formed in the armature frame 21 are individually wound in numerous turns and then wired to the lead lines by soldering.
The electrically wired coils 22a are arranged and assembled at a predetermined spacing with respect to the armature frame 21, at the time of which an insulating member 21e is used for an insulation between the lead lines of the coils 22a. However, those procedures have the problems in that appropriate lengths of the lead lines 22a have to be maintained and insulation between the lead lines 22d are required.
The detailed procedures of assembling the movable element 20 will be described with reference to FIGS. 3a-c. As shown in FIGS. 3a and 3b, at first, the armature frame 21 and the spacers 21b are assembled together, to which the coils 22a are coupled. Following these procedures, the coils 22a are wired to the lead lines. Next, as shown in FIG. 3c, the coils 22a are molded 22b to form the coil block 22.
In case of coupling the coils to the prior art armature frame 21 assembled with the spacers 21b, the groove 21a for assembling the coils has to be sealed. This makes it difficult to mold.
Therefore, it is an object of the present invention to provide a method for assembling an armature in which inner holes of coils are used to maintain a constant pitch between the coils and height of the coils, whereby a coil block can be readily assembled.
Another object of the present invention is to provide an armature making it possible to easily insulate lead lines of armature coils to each other and to readily perform the wiring of the coils, by using a printed circuit board.
Another object of the present invention is to provide an armature having two layered structure of armature frame facilitating to perform the wiring and molding of the coils.
According to one aspect of the present invention, there is provided a method for assembling an armature of a moving coil type linear motor, the method comprising the steps of: mounting coils, each having an inner hole, into a coil alignment block; covering a top surface of the coil alignment block with an upper cover so as to maintain a constant height of and pitch between the coils, and wiring the coils with each other; assembling a fixing cover and the coil alignment block to fix the coils; covering a bottom surface of the coil alignment block with a lower cover; and adhering with an epoxy adhesive the coils mounted onto the armature frame, and thereby fixing the coils.
According to another aspect of the present invention, there is provided a linear motor comprising: an armature frame; a plurality of armature coils, each coil having a plurality of leads; and a printed circuit board for use in the wiring of the leads and which is incorporated into the armature frame.
According to another aspect of the present invention, there is also provided a moving coil type linear motor comprising: a lower frame having therein a groove for assembling armature coils and integrally formed with spacers at a constant interval along the groove therein; and an upper frame over the lower frame and for sealing the groove at the time of molding the armature coils.